package com.salesmanager.core.utils.weichat;

import com.salesmanager.core.constants.WeiChatConstants;

import java.security.MessageDigest;
import java.util.*;

/**
 * Created by Liutong on 2016/6/2.
 */
public class WeiChatMD5Util {

    public static String createSign(String characterEncoding,SortedMap<Object,Object> parameters){
        StringBuffer sb = new StringBuffer();
        Set es = parameters.entrySet();//所有参与传参的参数按照accsii排序（升序）
        Iterator it = es.iterator();
        while(it.hasNext()) {
            Map.Entry entry = (Map.Entry)it.next();
            String k = (String)entry.getKey();
            Object v = entry.getValue();
            if(null != v && !"".equals(v)
                    && !"sign".equals(k) && !"key".equals(k)) {
                sb.append(k + "=" + v + "&");
            }
        }
        sb.append("key=" + WeiChatConstants.mch_key);
        String sign = WeiChatMD5Util.MD5Encode(sb.toString(), characterEncoding).toUpperCase();
        return sign;
    }




    private static String byteArrayToHexString(byte b[]) {
        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++)
            resultSb.append(byteToHexString(b[i]));

        return resultSb.toString();
    }

    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0)
            n += 256;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }

    public static String MD5Encode(String origin, String charsetname) {
        String resultString = null;
        try {
            resultString = new String(origin);
            MessageDigest md = MessageDigest.getInstance("MD5");
            if (charsetname == null || "".equals(charsetname))
                resultString = byteArrayToHexString(md.digest(resultString
                        .getBytes()));
            else
                resultString = byteArrayToHexString(md.digest(resultString
                        .getBytes(charsetname)));
        } catch (Exception exception) {
        }
        return resultString;
    }

    private static final String hexDigits[] = { "0", "1", "2", "3", "4", "5",
            "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };


    public static void main(String []args){
        SortedMap<Object,Object> parameters = new TreeMap<Object,Object>();
        parameters.put("amount",100);
        parameters.put("mch_appid","wx825ccde0759ed97e");
        parameters.put("check_name","OPTION_CHECK");
        parameters.put("mchid","1340116401");
        parameters.put("openid","o-ZO5wSXHcAM52vbCxsrg5qagwpk");
        String sign = WeiChatMD5Util.createSign("utf-8", parameters);
        System.out.println("&&&&&&&&&&&&&&&&&& sign = :"+sign);
        //201FADF8D4928024F9A7DDF4D5F0E90A
        //201FADF8D4928024F9A7DDF4D5F0E90A
    }
}
